Engine starter



July 16, 1963 w. c. WEHNER 3,09 34 ENGINE STARTER Filed July 22, 1959 3 Sheets-Sheet 1 INVEN TOR. WILLIAM C. WEHNER.

ATTORNEY uly '16, 963 w. c. WEHNER 3,097,634

ENGINE STARTER Filed July 22, 1959 3 Sheets-Sheet 2 INVENTOR.

WILLIAM C. WEHNER.

July 16, 1963 w. c. WEHNER 3,09 ,634

ENGINE STARTER Filed July 22, 1959 3 Sheets-Sheet 3 INVENTOR. WILLIAM C.WEHNER.

ATTORNEY- United States Patent 3,097,634 ENGINE STARTER William C. Wehner, Detroit, Mich, assignor, by mesne assignments, to Dura Corporation, a corporation of Michigan Filed July 22, 1959, Ser. No. 828,776 6 Claims. (Cl. 123-179) This invention relates to starting devices for internal combustion engines, particularly to engines of small horsepower output such as are commonly used to drive lawnmowers, and like vehicles.

The present invention is of the general type of that disclosed in my application Serial No. 774,976, filed November 19, 1958, now Patent 3,063,436, issued November 13, 1962, in which a coiled spring is wound by pushing the vehicle (a lawnmower) a few steps, whereupon the spring may be released and the stored energy applied to the crankshaft of the engine to start the engine. The present invention provides a different type of mechanism for connecting the ground engaging wheels to the spiral spring for winding the same as the vehicle is pushed forward, and its principal object is to provide a very simple, economical and eifective means for effecting that result.

A further object of the invention is to provide a simple and inexpensive starter for small engines of the type mentioned, in which a cable and drum form the connection between the ground engaging wheels and the starter spring.

A still further object is to provide a starter in which a constant torque is applied to the spiral spring during the winding movement.

For a description of a. preferred embodiment of the invention reference, is made to the following specification and to the accompanying drawings in which reference characters designate like par-ts referred to in the specification.

In the drawings:

FIG. 1 is a plan view of a rotary mower embodying the invention;

FIG. 2 is a fragmentary cross-sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is a fragmentary cross-sectional view taken on line 3-3 of FIG. 2;

FIG. 4 is a fragmentary cross-sectional view taken on line 44 of FIG. 3;

FIG. 5 is a fragmentary cross-sectional view taken on line 5-5 of FIG. 3;

FIG. 6 is a fragmentary cross-sectional view taken on line 66 of FIG. 1;

FIGS. 7, 8 and 9 are fragmentary cross-sectional views taken on lines "7-7, 8-8 and 99 respectively of 'FIG. 6;

FIG. 10 is a fragmentary cross-sectional view somewhat similar to FIG. 3 but showing a modified form of the invention; and 7 FIG. 11 is a fragmentary cross-sectional view taken on line 1111 of FIG. 10.

Referring now to the drawings in more detail and particularly to FIGS. 1 to 9 thereof, the invention is embodied in a rotary lawnmower having a deck 10 with a skirt 12 on which are mounted a front axle 14 carrying front wheels 16, and a rear axle 18 carrying rear Wheels 20 and 21. An engine 22 is mounted on the desk. It may be either a twio cycle or four-cycle type provided with the usual flywheel (not shown). It has a vertically disposed crankshaft 24 to which is attached a cutting blade 26. A handle 28 with the usual grip (not shown) is attached to the skirt 12 at the rear fior pushing and guiding the mower.

Mounted on top of the engine by fastenings 30 is a housing 32. This housing contains a flat spiral spring '34 (see FIGS. 3 and 5) similar to a clock mainspring attached at one end to a starter shaft 36 by fastenings 38 and at the other end to the housing at 40. The starter shaft is aligned with crankshaft 24. A plate 42 is fastened into the housing by screws 44 and the starter shaft is journalled in a bearing 46 in plate 42 and a bearing 4-8 in housing 32.

Fastened to the lower end of the starter shafit 36 is a radial arm 50 which carries a radially swingable dog 52. The dog is pivoted on a pin having a large head 54 around which one end of a spring 56 is wound and attached to the dog 52. The free end of the spring extends outwardly and upwardly and frictionally engages the unlderside of plate 42.

Attached to the crank shaft 24 by a pin 58 is a cup member 60 having on the interior of its upstanding pcripheral flange a series of teeth 62 engageable at certain times by dog 52.

On the upper end of starter shaft 36 and fixed thereto is a sheave 64 having a rather deep groove to receive several turns of a cable 66. The purpose of this will appear presently.

The right hand end of axle 18 (see FIGS. 6 and 8) is square. This square end fits into a square socket in a boss 68 on a plate 70 attached to the right hand wiheel 21 by screws 72 and is held therein by a cap plate 74 and screw 76. Thus the axle 18 is fixed to wheel 21 and must rotate with it. The left hand wheel 20 is mounted to ro tate freely on axle 18 so that the mower may be easily turned around curves and corners.

'Rotatably mounted on the axle 18 is a drum 78. Both ends of the drum are of the same size, but intermediate the ends thereof it is tapered (see FIG. 6) to form a frustrum of a cone. The drum 78 is arranged to be put into, and released from, driven engagement with the axle by a clutch mechanism part of which is the drum itself. A collar 80 having four axially extending projections '82 (see FIGS. 6 and 7) is attached to the axle by pin 84. The end of the drum 78 adjacent to the collar has four indentations to receive the projections 82 when in clutched position. The other end of the drum has a cylindrical groove 86 therein to receive the clutch actuating mechanism. A helical compression spring 88 surrounds the axle and lies between the skirt 12. and the right hand end of drum 78, tending to push the drum to the left to keep it in engagement with collar 80.

A vertical rod 90 is pivotally mounted in a bearing 92 in the deck 10 and in another bearing 94 in a bracket 96 attached to skirt 12. This rod carries a pair of pins 98 extending radially therefrom to form a yoke straddling the drum and received in the groove 86 (see FIGS. 6 and 9). Fastene-d to the upper end of rod 90 is a lever 100 which is fastened to one end of a Bowden wire 102. The other end of the wire is slidably mounted on the handle 28 and may be operated in any suitable well known manner.

The deck 10 is provided with an opening 104 above that portion of the drum 78 upon which the cable '66 winds and through which the cable extends. A U-shaped bracket 106 is mounted on the engine housing 22. This bracket has an idler roller 108 rotatably mounted in the arms thereof, and cable 66 extends over it. The purpose of the roller 108 is to carry the cable to the level of the sheave '64 so that the cable 66 will wind onto it smoothly.

The operation of the invention is as follows:

Let it be assumed that the engine 22 is at rest and it is desired to start it. The Bowden wire 102 is pulled, thereby moving drum 78 to the left (as viewed in FIG. 6), through the medium of lever 100 and yoke 98, into interlocking engagement with collar 80. The mower is then pushed forwardly causing drum 7% to turn and wind cable 66 onto it. As the cable is wound onto the drum, it unwinds from the sheave 64, turning the latter in a counter-clockwise direction and thereby winding the spiral spring 34. After a few turns of the sheave the spring will be fully wound and it will be impossible to push the mower further without sliding the driving wheel 21. The wire 102 is then pushed, disengaging the drum 78 from collar 80 and allowing the drum to rotate freely on the axle and spring 34 to unwind rapidly. The wire 102 may be held in its forwardly pushed position by any suitable latch means on the handle 28. As the spring unwinds it carries dog 52 with it and because spring 56 frictionally engages plate 42 the dog is moved into engagement with a tooth 62 thus connecting the shaft 36 with crankshaft 24. The stored energy of spring 34 is imparted to the crankshaft to spin the latter and start the engine. As soon as the engine has started it causes the cup member 60 to overrun the dog 52 and release it from engagement with the cup member, whereupon the mower operates in its normal fashion.

At the same time that spring 34 unwinds to start the engine, it rewinds cable 66 onto sheave 64, and unwinds it from drum 78. The drum, being disengaged from collar 80, there normally would be a tendency for the drum to spin rapidly on the axle. Spring 88 however acts as a brake, since it frictionally engages both the end of drum 78 and the skirt 12 of the deck 10, thereby preventing the drum from overrunning and tending to rewind the cable 66 on the drum.

It will be noted that because the cable 66 is wound upon the sheave 64 in a single plane (see FIG. 3), as it unwinds, the effective diameter of the sheave becomes smaller, thereby reducing the torque turning the shaft 36. Furthermore, as spring 34 is wound its tension is increased. Since both of these factors would norm-ally increase the force required to push the mower during starting, the drum 78 is tapered, as previously described. Thus as cable 66 is wound along the drum the power factor of the drum is increased to compensate for the increase in the torque required to wind spring 34.

FIGS. and 11 show a slightly modified form of the invention. The principal difference between this form of the invention and that previously described is that the starting mechanism is concealed by the deck. Otherwise it is to all intents and purposes the same. A deck 120 supports a motor 122 from which a crankshaft 124 depends. The crankshaft carries an internally toothed cup member 126 fixed thereto to which a cutting blade 128 is fastened. The deck is provided with a depression 130 on the bottom of which a cup 132 is fastened. Inside of the cup is a fiat spiral spring 134, one end of which is attached to the side wall of cup 132. The other end is attached by a screw 136 to a sleeve 138 which is a part of a sheave 140 located in depression 130' in the deck 120. The sleeve 138 is keyed or otherwise fixed to a coaxial inner sleeve 142. The lower end of sleeve 142 has an arm 144 extending radially therefrom on which .a dog 146 and a spring 148, similar to dog 52 and spring 56 respectively previously described, are mounted in the same manner.

Attached at one end to the sheave 140 and wound into the groove thereof is a cable 150. The cable runs over a roller 152 mounted beneath the deck 120 and is attached at 156 to a drum 154 the same as drum 78 previously described.

The operation of this form of the invention is essentially the same as the other form. As the vehicle is pushed drum 154 winds cable 150, turning sheave 140 and tensioning the spring 132. After the spring is fully wound the drum 154 is declutched as before, releasing the energy of the spring which spins sleeves 138 and 142 with the dog 146 on the latter clockwise. The dog flies out and engages a tooth in cup member 126 thereby coupling the shaft 124 with the spring 134. The stored energy of the spring can then start the engine. As soon as the engine starts the crankshaft 124 and cup member 126 overrun the dog 146 thereby releasing the latter from engagement with the cup member and the engine operates normally to drive cutter bar 128.

From the foregoing it will be seen that the present invention provides a very simple and effective starting mechanism for small vehicle engines that can be actuated simply by pushing the vehicle in the normal manner until resistance to forward movement indicates that the spring is fully wound. The Bowden wire is then pushed to disengage the starter and the engine starts automatically.

While I have shown a specific embodiment of the invention as applied to a particular device, it will be understood that this has been done for the purpose of illustration,

and is not to be considered as limiting the application or scope of the invention.

I claim:

1. In combination with a hand guided, walking attendant type of implement having a deck, an axle and a wheel fixed on said axle, an engine mounted on said deck, said engine having an engine shaft, a coil spring carried by the implement, a drum of frusto-conical configuration mounted on said axle for rotary movement relative thereto, clutch means on the axle releasably connected to the drum for rotating the drum with the axle when said clutch means is engaged, a cable fastened to the drum adjacent its larger end for winding thereon, means connecting said cable to said spring for winding the latter upon rotation of the drum, and means for applying the stored energy of the spring to the engine shaft for starting the engine.

2. In combination with a wheeled vehicle having an engine mounted thereon, said engine having a crankshaft, means for starting said engine comprising a drum of frusto-conical shape rotatably mounted on said vehicle, means for releasably connecting said drum to one of the wheels of said vehicle whereby said drum may be rotated upon rotation of said wheel, a spring mounted on said vehicle, a cable connected to said drum adjacent the larger end thereof for winding thereon, means connecting said cable to said spring for tensioning said spring when said cable is wound on said drum, and means for imparting the stored energy of the spring to the engine crankshaft to start the engine when the drum is released from its connection with the wheel.

3. In combination with a wheeled vehicle having an engine mounted thereon, said engine having a. crankshaft, means for starting said engine comprising a spring mounted on said vehicle, means connecting a wheel to said spring for tensioning said spring as said vehicle is manually propelled, said means comprising a drum adapted to be rotated by a wheel, a cable connected to said drum and adapted to be wound thereon, said drum being of frusto-conical shape thereby to exert a substantially constant torque on said spring as said cable is wound thereon, and means for imparting the stored energy of said spring to said crankshaft to start the engine.

4. In combination with a vehicle having a deck, an axle rotatably mounted on said deck, and wheels on said axle, one of said wheels being fixed to said axle, an engine mountd on said deck, said engine having a crankshaft, a coil spring carried by said vehicle, a drum having a conical portion mounted on said axle for rotary movement relative thereto, clutch means on said axle releasably connected to the drum for rotating the drum with the axle when the clutch means is engaged, a cable fastened to the drum adjacent the larger end of said conical position for winding thereon, means connecting the cable to said spring for winding the latter upon rotation of the drum, and means including a clutch for connecting the spring to the crankshaft for applying the stored energy of the spring to the crankshaft for starting the engine.

5. A vehicle having a deck, axles on said deck beneath the latter, wheels on said axles, one of said wheels being fixed to its axle to rotate the latter when the vehicle is pushed, an engine mounted on the deck said engine having a cnankshaft, :a coil spring mounted on the vehicle and adapted to be tensioned, means for releasably connecting the spring to the crankshaft, means including a drum of frusto-conical shape mounted on said axle for rotation by the wheel fixed to the latter, said deck having an opening therein above said drum, a cable attached to said drum to be wound thereon when the vehicle is pushed forwardly, said cable passing through the opening in the deck, means connecing the cable to the spring to tension the latter as the cable is wound onto the drum, means for releasing the drum to permit the drum to rotate freely on the axle, and means for imparting the stored energy of the spring to the crankshaft to start the engine when the drum is released.

References Cited in the file of this patent UNITED STATES PATENTS Markmann July 2, 1912 Barr July 11, 1961 FOREIGN PATENTS Great Britain Aug. 23, 1821 

1. IN COMBINATION WITH A HAND GUIDED, WALKING ATTENDANT TYPE OF IMPLEMENT HAVING A DECK, AN AXLE AND A WHEEL FIXED ON SAID AXLE, AN ENGINE MOUNTED ON SAID DECK, SAID ENGINE HAVING AN ENGINE SHAFT, A COIL SPRING CARRIED BY THE IMPLEMENT, A DRUM OF FRUSTO-CONICAL CONFIGURATION MOUNTED ON SAID AXLE FOR ROTARY MOVEMENT RELATIVE THERETO, CLUTCH MEANS ON THE AXLE RELEASABLY CONNECTED TO THE DRUM FOR ROTATING THE DRUM WITH THE AXLE WHEN SAID CLUTCH MEANS IS ENGAGED, A CABLE FASTENED TO THE DRUM ADJACENT ITS LARGER END FOR WINDING THEREON, MEANS CONNECTING SAID CABLE TO SAID SPRING FOR WINDING THE LATTER UPON ROTATION OF THE DRUM, AND MEANS FOR APPLYING THE STORED ENERGY OF THE SPRING TO THE ENGINE SHAFT FOR STARTING THE ENGINE. 